Confused

When an object is dropped, the distance it falls in t seconds, assuming that air resistance is negligible, is given by s(t) =4.905t- where s(t) is in meters (m). If a stone is dropped from a cliff, assuming that air resistance is negligible, find the velocity and acceleration of the stone after it had been falling for 8 sec. m The velocity of the stone is sec (Type an integer or decimal rounded to two decimal places as needed.)